The Environmental Immunology laboratory studies the adverse effects on the immune system which may result from occupational, accidental, or therapeutic exposure to environmental chemicals, biological materials or therapeutic agents. The ongoing objectives include efforts to: (1) evaluate and characterize the influence of environmental agents or selected therapeutics (e.g. AIDS drugs) on immune function and relate the observed alterations to an organism's ability to resist infectious disease and neoplasia, as well as general and specific organ toxicity, (2) continue to refine and develop assays which examine immunologic endpoints and improve their predictive value for human exposures (3) examine the cellular and molecular mechanisms which lead to alterations in the immune response, (4) examine the role of inflammatory and growth- promoting cytokines in the development of toxicity and neoplasia in the skin, lung and liver. Specific studies include: (a) characterization of cytokines of significance in arsenic-induced neoplasia, particularly in the skin and lung using in vitro studies in arsenic-treated rodent and human cell cultures and in vivo rodent models of arsenic exposure; (b) examination of the mechanism whereby TCDD alone or in combination with TNF alters the expression of specific cellular proteins resulting in hepatotoxicity; (c) the dysregulation of proinflammatory cytokines in the skin by the pro-oxidant, anti-psoriatic drug, anthralin. Studies examining the induction of CYP1A1 and ALDH-3 by TCDD in immune cells and tissues, and how this induction related to Ah receptor expression were completed within this time period.